Nuclear power station for a gaseous working medium

ABSTRACT

The nuclear power station is constructed so that a working gas is conducted through a closed cycle. The reactor, power station and heat exchangers are accommodated in a pressure tight vessel while the starting point and end point of the working gas thermal work path are disposed in a sub-chamber with the power station.

United States Patent 1191 Zimmermann 45] July 24, 1973 1 1 NUCLEAR POWERSTATION FOR A GASEOUS WORKING MEDIUM [75] Inventor: UlrichZimmermann,Winterthur,

21 App]. No.: 822,220

[30] Foreign Application Priority Data May 17, 1968 Switzerland 7370/68[52] U.S. Cl 176/60, 176/65, 176/87 [51] Int. Cl. G211: 19/28 [58] Fieldof Search 176/59, 40, 60, 87, 176/53, 55, 57, 65, 58

[56] References Cited UNITED STATES PATENTS 3,175,953 3/1965 NBIIEI6161. 176/60 3,178,354 4/1965 Vann et a1. 176/37 X 3,371,017 2/1968Coast et a1 176/87 2,277,800 4/1968 Spillmann 176/60 X 3,425,907 2/1969Bonsel et a1... 176/50 X 3,444,038 5/1969 Schabert .1 176/65 X FOREIGNPATENTS OR APPLICATIONS 799,212 8/1958 Great Britain 6,606,033 11/1966Netherlands OTHER PUBLICATIONS Berman, Paul A., Westinghouse Engineer,Sept. 1960, pp. 146-149.

Primary Examiner-Carl D. Quarforth Assistant Examiner-E. E. LehmannAttorney-Kenyon and Kenyon Reilly Carr & Chapin [57] ABSTRACT Thenuclear power station is constructed so that a working gas is conductedthrough a closed cycle. The reactor, power station and heat exchangersare accommodated in a pressure tight vessel while the starting point andend point of the working gas thermal work path are disposed in asub-chamber with the power station.

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lnventor= Z/MMERMHNN BY NUCLEAR POWER STATION FOR A GASEOUS WORKINGMEDIUM This invention relates to a nuclear power station and moreparticularly to a nuclear power station comprising a nuclear reactor forheating a working gas used to operate a power station.

Official regulations by numerous countries contain safety regulationsconcerning the flow of working media and the construction andaccommodation of machinery in nuclear power stations in order to preventany escape of contaminated working media in the event of any damage tothe plant. If the working medium is a vapor, simple steps are sufficientto comply with these regulations. For example, a construction has beenevolved in which a steam generator is accommodated in a reactor pressurevessel and the heat produced by the reactor is carried out of thereactor to the steam generator heating surfaces by means of a recycledheat vehicle gas. In this construction, neither the water nor the steamcan come into contact with a contaminated medium so that the entiresteam power plant can be erected outside the reactor vessel.

However, conditions are quite different in nuclear power stationsoperated with gaseous working media. For example, since the gases usedfor the thermal work process have had a lower specific heat and lowercoefficients of heat transfer than evaporable working media, the workinggases have required large volumes for such stations. These large volumeshave been such that the only constructions evolved heretofore have beenthose in which the reactor has been accommodated in a hermeticallyscalable machine room, with the intent of preventing any further dangerby sealing off the entire machine room after the operating personnelhave escaped, in the event of any accident occurring. Despite the outlayrequired, a precaution of this type has not been fully satisfactorybecause it has not been fully operative immediately upon the occurrenceof an accident.

Accordingly, it is an object of the invention to practi cally completelyprotect the space outside a pressure vessel of a nuclear reactor plantutilizing a gaseous working medium.

It is another object of the invention to practically fully utilize theinterior of a nuclear reactor vessel.

It is another object of the invention to reduce flow resistance to agaseous working medium at points of high specific volume.

It is another object of the invention to reduce the number of openingsthrough a reactor pressure vessel to the outside.

It is another ohiect of the invention to obtain a minimum quantity ofworking medium within a nuclear power station.

It is another object of the invention to reduce piping to an absoluteminimum within a nuclear power station.

Briefly, the invention provides a nuclear power station in which anuclear reactor, the components of a power plant and heat exchangers fora gaseous working medium are accommodated in a pressure tight concretevessel. In addition, the nuclear reactor is disposed in one sub-chamberof the vessel while the power plant and heat exchangers are disposed inanother subchamber. Also, in order to carry the working gas from astarting point of the thermal work path to the end point thereof, thecomponents of the power plant are at least partly successivelyinterconnected by tubular ducts and the starting point and the end pointof the work path are disposed in the sub-chamber surrounding the powerplant components so that the working gas flows back from the end pointthrough this subchamber to the starting point. The work cycle is thus aclosed cycle.

Since the reactor, the power plant and the heat exchangers carrying theworking gas, and the ducts and chamber parts required to form the cycleare accommodated in the pressure tight concrete vessel, only themechanical or electrical power produced and the cooling water which doesnot come into contact with the contaminated gas have to be withdrawnfrom the concrete vessel. The space outside the concrete vessel is thuspractically completely protected against contaminated gas while theinterior of the reactor vessel is practically fully utilized. Further,reduction of the length of the piping and the increased flowcross-sections in the zone where the working gas has a high specificvolume, greatly reduces losses due to flow resistances.

In one embodiment, the heat exchangers are dis posed within the interiorspace of the sub-chamber containing the power plant whereas in a secondembodiment, the heat exchangers are disposed in the walls of thesub-chamber in individual cell-like recesses. In either embodiment, theworking medium flows at minimum pressure and approximately minimumtemperature.

These and other objects and advantages of the invention will become moreapparent from the following detailed description and appended claimstaken in conjunction with the accompanying drawings in which:

FIG. 1 illustrates a part cross-section view of a nuclear power stationconstruction in accordance with the invention;

FIG. 2 illustrates a view taken on line 22 of FIG.

FIG. 3 illustrates a similar view as FIG. I of a modilied nuclear powerstation according to the invention; FIG. 4 illustrates a view taken online 4-4 of FIG.

FIG. 5 illustrates an enlarged view of a heat exchanger of the stationof FIG. 3;

FIG. 6 illustrates an enlarged view of another heat exchanger of thestation of FIG. 3; and

FIG. 7 graphically illustrates a temperature-entrophy cycle curve of theworking medium in a nuclear power station constructed according to theinvention.

Referring to FIGS. 1 and 2, the nuclear power station includes a casingin the form of a pressure tight and gas tight vessel 1 of reinforcedconcrete. The vessel I is subdivided into a pair of sub-chambers 2, 4which may or may not be sealed off from one another by a partition sincethe vessel I forms an absolutely gas tight enclosure for theentirestation. In addition, a nuclear reactor 3 is disposed in the uppersub-chamber 2 while a pair of power plants 5.], 5.2 are located in thelower sub-chamber 4. The partition between the subchambers 2, 4 mustwithstand at least the pressure difference between the two chamberpressures and may be designed for higher pressure differences shouldsuch assume greater values, e.g. in the event of an accident.

Each power plant 5.1, 5.2 is constructed with identical sub-stations andtherefore only the sub-station of one plant 5.2 is shown completely.Each sub-station includes a low pressure compressor 6.1, 6.2 which has apair of oppositely disposed open feed pipes for drawing in working gas,a high pressure compressor 7.1, 7.2 and a gas turbine 8.1, 8.2,respectively which are mounted on a common shaft. Each common shaft isled out through the concrete vessel wall in gas tight and radiationproof manner to transmit a mechanical output to an electrical generator9.1, 9.2 respectively.

The vessel 1 further encases heat exchangers for a flow of working gastherein. The heat exchangers provided inside the concrete vesselcomprise intermediate coolers 10.1, 10.2 for cooling the working gasbetween the low pressure compressors 6.1, 6.2 amd high pressurecompressors 7.1, 7.2 and a number of recuperators 11 which serve the twosub-stations jointly and recoolers 12 which also serve both sub-stationsjointly. Each low pressure compressor 6.1, 6.2 is connected to theintermediate cooler 10.1, 10.2 by a duct 14.1, 14.2 of tubular shapewhile ducts 15.1, 15.2 carry the gas from the intermediate coolers 10.1,10.2 to the high pressure compressors 7.1, 7.2. A duct system 16 isconnected to the two sub-station high pressure compressors 7.1, 7.2 tocombine the working medium of the two halves and uniformly distributethe medium to a battery of recuperators 1 1 having suitable flow throughtubes therein. The outlets from the recuperators 11 are also joinedtogether by means of a duct system 17 leading to an inlet of the reactor3.

Ducts 18.1, 18.2 are provided between the outlet of the reactor 3, as isknown, to carry the working gas separately to each of the turbines 8.1,8.2. The turbines 8.1, 8.2 are further connected via ducts 19.1, 19.2 toa distribution chamber 20 mounted from the floor 26 in order that theexpanded working gas from the turbines 8.1, 8.2 can be distributed tothe various recuperators l1 suspended from the chamber 20 to flow overthe flow through tubes therein in counterflow to the flow in the tubes.The working gas can then flow, as indicated, from the recuperators 11 tothe part of the chamber 4 situated beneath the intermediate floor 26which supports the power plants 5.1, 5.2 and finally through there-coolers 12 at the part of the chamber 4 above the intermediate floor26.

It is apparent that the nuclear power station provides a working gaspath which begins at the entry points 13.1, 13.2 of the low pressurecompressors 6.1, 6.2 and terminates at the outlet 21 of the re-coolers12. From the outlet 21 as far as the inlet 13, the working medium flowsthrough the area surrounding the power plants 5.1, 5.2 at substantiallyminimum cycle temperature and minimum cycle pressure. At the same time,the speed of the working medium is reduced to a fraction so that,despite the large volume in this state of the gas, there is noappreciable pressure drop due to resistance to flow. In this way, it isalso possible to dispense with ducting of very large cross-sectionswhich would otherwise be very difficult to accommodate.

All points of the interior of the concrete vessel 1 have a pressureabove atmospheric and equal at least to the minimum cycle pressure.Since the two parts of the chamber 4 which are interconnected by there-coolers 12, however, have only an insignificant pressure differencedue to the resistance to the flow of the gas in the re-coolers 12, thispressure difference would not be sufficient to bear the intermediatefloor with the power plants. The floor 26 must therefore simply bedimensioned according to the weight of the power plant components thathave to be supported.

An access 24 to the interior of the vessel 1 is provided; however, thisaccess 24 must be kept sealed during operation so that any contaminatedgas cannot escape from the interior even if an accident of some kindcauses the entire gas contents to be distributed to the two sub-chambers2, 4 until the pressure is completely equalized. In such a case, thepressure in the subchamber 4 would have to rise considerably whileprobably dropping in the sub-chamber 2.

In order to introduce and withdraw cooling water to and from theconcrete vessel 1 for the intermediate coolers 10.1, 10.2 and re-coolers12, pipes 30, 31 are respectively connected to each and are led outthrough the wall of the vessel 1 via a single sealing system 32.

Referring to FIGS. 3 and 4, wherein like parts as above are designedwith like reference characters, the nuclear reactor station can bemodified so that the heat exchangers 10, 11, 12 are disposed around thereactor 3 in individual cell-like recesses in the wall of the vessel 1.As above, the working path of the working gas again begins at an initialpoint 13.1, 13.2, passes through the low pressure compressors 6.1, 6.2(only one of which is shown), and then passes through the ducts 14 tothe intermediate coolers 10.1, 10.2 respectively.

Referring to FIGS. 3 and 5, in flowing through a cooler 10, the workinggas flows upwardly in the duct 14 over suitable flow through tubesconnected between lines 30 to a source of coolant, e.g. water, and to anoutlet. Thereafter, the working gas passes downwardly over the exteriorof the duct 14 within the duct 15 which may be concentrically disposedto the duct 14 and directed to the high pressure compressor (not shown).The working medium then flows back through the ducts 15 to the highpressure compressor 7.1, 7.2 and then through a duct system 16 whichdistributes the gas to the individual recuperators 11.

Referring to FIGS. 3 and 6, in flowing through a recuperator 11, thecooled working gas flows up through a duct 16 at the center of therecuperator 11 and thence downwardly through a plurality of suitableflow through tubes connected between suitable manifolds at the tworespective ends of the duct 16. The working gas then continues throughindividual pipes 51 to the subchamber of the nuclear reactor.

Referring to FIG. 6, the working gas then passes from the sub-chamber 2through pipes 18.], 18.2 to the turbines 8.1, 8.2 and via ducts 19.1,19.2 to the distribution chamber 20 from which the path then continuesthrough individual pipes 53 back to the recuperators 1 1 and on to there-coolers 12.

Referring to FIGS. 3 and 6, in flowing back through a recuperator 11,the heated working gas enters via a pipe 53 and passes upwardly over thetubes (as shown) in counter flow and in heat exchange relation to thecooler working gas in the tubes. The working gas then continues upwardlyover suitable flow through tubes in a re-cooler 12 connected betweenlines 31 to a source of coolant, e.g. water, and to an outlet.Thereafter, the working gas passes downwardly via an annular duct 54which may be concentric to the duct 53.

Referring to FIG. 3, the working gas then passes from the annular ducts54 in the vessel wall to the end point 21 in the sub-chamber 4. The gaspasses at minimum pressure and approximately minimum temperature throughthe chamber surrounding the power plant components and finally passesback to the initial point 13, which completes its work cycle.

The nuclear reactor station of the first exemplified embodiment thusreduces the piping required to an absolute minimum to comply with thegeneral principle of using the minimum size of machine room and hencethe minimum pressure vessel volume. This has proved to be surprisinglysuccessful by the provision of an intermediate floor in the chamber 4.Another advantage of this exemplified embodiment is the extremely simplegeometric shape of the machine room, which results in an easilycalculated and economically constructed pres sure vessel. The simpleshape of the machine room also provides important advantages with regardto the provision of any sheet-metal lining required for the room.

The nuclear reactor station of the second exemplified embodiment on theother hand, allows the heat exchangers to be readily removable andfunctions on a minimum quantity of working medium. In addition, thislatter embodiment enables the reactor station to be constructed belowground even when there is a relatively high ground water level and wherea minimum overall height is necessary. For example, the nuclear powerstation can be constructed in accordance with the power plant describedin US. patent application, Ser. No. 762,185, filed Sept. 16, 1968. Thisresults in a surprisingly simple solution as regards space, and despitethe relatively intensive fissuring of the concrete, enables a relativelysimple structural shape to be used, which is easy to line.

Referring to FIG. 7, on a temperature-entrophy T, S graph, the workcycle is represented substantially as a closed gas turbine process. Atpoint 60 which corresponds to the starting point 13 and the end point21, the working medium has its minimum temperature and minimum pressureand enters the low pressure compressor 6 in this state. The workingmedium is then cooled in the intermediate cooler from state 61 to state62, and then brought to a state 63 in the high pressure compressor 7which is the maximum cycle pressure. The working medium then flowsthrough the recuperators 11 as far as state 64 and is finally continuedin the reactor 3 to the maximum temperature state at point 65.Subsequent expansion is the turbines 8 causes the working medium to bebrought back to a lower pressure and lower temperature at state 66. Theworking gas then yields up heat to the state 67 in the recuperators l1,whereupon re-cooling to state 60 is carried out in the re-coolers 12.The heat withdrawn from the working gas between the states 66 and 67. isrestored to it in the recuperators 11 between the states 63 and 64.

In both nuclear power stations described above, the working medium atstate 60 is in that part of the chamber 4 which surrounds power plantcomponents 6, 7, 8 and flows through this chamber from the end point 2]of the work path to the starting point [3 to complete the work cycle.Also, in both stations, the working medium flows at minimum pressure andapproximately minimum temperature corresponding to state 60 through thechamber 4 upon passing back to the starting point 13 from the end point2!.

In the nuclear power station shown in FIGS. 1 and 2, the working mediumalso flows at state 67 between recuperators 11 and the re-coolers 12freely in that part of the chamber 4 which is situated beneath the floor26. The flow through the open chamber is very favorable in this casebecause the specific volume is very high as a result of the elevatedtemperature here.

The invention further provides a nuclear reactor station which is ofsimple construction and which increases safety while achieving aconsiderable saving in space and reducing power losses.

What is claimed is:

l. A nuclear power station comprising a pressure vessel divided into atleast a first chamber and a second chamber;

a nuclear reactor sealingly disposed in said first chamber for heating aworking gas therein;

a power plant having a turbine and a compressor sealingly disposed insaid second chamber, said turbine being disposed in said second chamberto receive the heated working gas from said reactor in said firstchamber to produce a mechanical output; and

a plurality of heat exchangers disposed in said pressure vessel forcooling the heated working gas exhausted from said turbine, said heatexchangers being connected with said turbine and compressor of saidpower plant to convey the working gas therethrough from a starting pointwithin said second chamber disposed adjacent said compressor, throughsaid compressor, said reactor, said turbine and said heat exchangers toan end point within said second chamber, said end point being spacedfrom said starting point and opening into said second chamber, saidworking gas completely filling said second chamber and flowing from saidend point into and through said second chamber about said turbine andsaid compressor of said power plant to said starting point.

2. A nuclear power station as set forth in claim I wherein said heatexchangers are disposed in said second chamber and wherein anintermediate floor is disposed in said second chamber to separate saidsecond chamber into two parts.

3. A nuclear power station as set forth in claim 2 wherein a first partof said two parts contains said power plant and a second part containsat least some of said heat exchangers.

4. A nuclear power station as set forth in claim 3 wherein said heatexchangers include a plurality of recoolers mounted in said intermediatefloor at said end point.

5. A nuclear power station as set forth in claim 3 wherein said heatexchangers include a plurality of recuperators mounted in said secondpart for cooling a flow of the working gas and a plurality of re-coolersmounted in said intermediate floor at said end point and connected tosaid recuperators to further cool the flow of working gas passing fromsaid recuperators to said power plant.

6. A nuclear power station as set forth in claim 5 wherein saidrecuperators each have an inlet projecting into said second part belowsaid floor and an outlet projecting into said first part above saidfloor.

7. A nuclear power station as set forth in claim 5 which furthercomprises a distribution chamber mounted from said floor and connectedbetween said power plant and said recuperators for distributing theworking gas to said recuperators.

8. A nuclear power station as set forth in claim 7 wherein saidrecuperators are suspended from said distribution chamber.

9. A nuclear power station as set forth in claim 2 wherein said powerplant is supported on said intermediate floor.

10. A nuclear power station as set forth in claim 1 wherein said powerplant includes a low pressure compressor having at least one open feedpipe at said starting point for drawing working gas thereinto.

11. A nuclear power station as set forth in claim 10 wherein said powerplant further includes a high pressure compressor connected to said lowpressure compressor and said heat exchangers include a cooler connectedbetween said low pressure compressor and said high pressure compressorfor cooling a flow of working gas passing therebetween.

12. A nuclear power station as set forth in claim 11 wherein saidcompressors and said cooler are mounted in the second chamber.

13. A nuclear power station as set forth in claim 1 wherein saidpressure vessel has a wall containing recesses therein. and wherein atleast some of said heat exchangers are mounted in said recesses.

l4. A nuclear power station as set forth in claim 13 wherein siad heatexchangers include a plurality of recuperators connected to said powerplant and mounted in said recesses.

15. A nuclear power station as set forth in claim [3 wherein said heatexchangers include a plurality of recoolers at said end point mounted insaid recesses.

16. A nuclear power station as set forth in claim 13 wherein said powerplant includes a low pressure compressor at said starting point fordrawing in working medium and a high pressure compressor connected tosaid low pressure compressor, and wherein said heat exchangers includecoolers connected between said compressors and mounted in said recessesfor cooling a flow of working gas passing between said compres- SOIS.

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2. A nuclear power station as set forth in claim 1 wherein said heatexchangers are disposed in said second chamber and wherein anintermediate floor is disposed in said second chamber to separate saidsecond chamber into two parts.
 3. A nuclear power station as set forthin claim 2 wherein a first part of said twO parts contains said powerplant and a second part contains at least some of said heat exchangers.4. A nuclear power station as set forth in claim 3 wherein said heatexchangers include a plurality of re-coolers mounted in saidintermediate floor at said end point.
 5. A nuclear power station as setforth in claim 3 wherein said heat exchangers include a plurality ofrecuperators mounted in said second part for cooling a flow of theworking gas and a plurality of re-coolers mounted in said intermediatefloor at said end point and connected to said recuperators to furthercool the flow of working gas passing from said recuperators to saidpower plant.
 6. A nuclear power station as set forth in claim 5 whereinsaid recuperators each have an inlet projecting into said second partbelow said floor and an outlet projecting into said first part abovesaid floor.
 7. A nuclear power station as set forth in claim 5 whichfurther comprises a distribution chamber mounted from said floor andconnected between said power plant and said recuperators fordistributing the working gas to said recuperators.
 8. A nuclear powerstation as set forth in claim 7 wherein said recuperators are suspendedfrom said distribution chamber.
 9. A nuclear power station as set forthin claim 2 wherein said power plant is supported on said intermediatefloor.
 10. A nuclear power station as set forth in claim 1 wherein saidpower plant includes a low pressure compressor having at least one openfeed pipe at said starting point for drawing working gas thereinto. 11.A nuclear power station as set forth in claim 10 wherein said powerplant further includes a high pressure compressor connected to said lowpressure compressor and said heat exchangers include a cooler connectedbetween said low pressure compressor and said high pressure compressorfor cooling a flow of working gas passing therebetween.
 12. A nuclearpower station as set forth in claim 11 wherein said compressors and saidcooler are mounted in the second chamber.
 13. A nuclear power station asset forth in claim 1 wherein said pressure vessel has a wall containingrecesses therein, and wherein at least some of said heat exchangers aremounted in said recesses.
 14. A nuclear power station as set forth inclaim 13 wherein siad heat exchangers include a plurality ofrecuperators connected to said power plant and mounted in said recesses.15. A nuclear power station as set forth in claim 13 wherein said heatexchangers include a plurality of re-coolers at said end point mountedin said recesses.
 16. A nuclear power station as set forth in claim 13wherein said power plant includes a low pressure compressor at saidstarting point for drawing in working medium and a high pressurecompressor connected to said low pressure compressor, and wherein saidheat exchangers include coolers connected between said compressors andmounted in said recesses for cooling a flow of working gas passingbetween said compressors.